CN211478151U - Array probe for eddy current testing of curved surface workpiece - Google Patents
Array probe for eddy current testing of curved surface workpiece Download PDFInfo
- Publication number
- CN211478151U CN211478151U CN202020114618.1U CN202020114618U CN211478151U CN 211478151 U CN211478151 U CN 211478151U CN 202020114618 U CN202020114618 U CN 202020114618U CN 211478151 U CN211478151 U CN 211478151U
- Authority
- CN
- China
- Prior art keywords
- coil
- eddy current
- workpiece
- probe
- coils
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
The utility model discloses an array probe for curved surface work piece eddy current testing, it is by a plurality of the same size, the same coil of parameter arrange the flexible material in order to encircle the array mode of arranging of work piece to the embedding and the overall structure that the profile modeling base that is examined the three-dimensional appearance of work piece and suits formed. The flexible array eddy current probe has the advantages of improving the detection efficiency and inhibiting the interference, and the flexible array eddy current probe is arranged by a plurality of coils according to the shape of a workpiece in a surrounding way, so that the influence of the edge effect is effectively eliminated; the flexible material is used in a matched mode, the probe is embedded into the base structure matched with the three-dimensional model of the workpiece, the probe is attached to the surface of the workpiece, and interference caused by different distances between the probe and the surface of the workpiece is effectively reduced.
Description
Technical Field
The utility model relates to a nondestructive test technical field, concretely relates to array probe for curved surface work piece eddy current testing.
Background
There are many workpieces made of metal materials with complex shapes and curved detection surfaces, such as small-diameter pipes, turbine blades of engines, airplane hubs and the like, which need to be detected by surface and near-surface defects. For such workpieces, conventional nondestructive inspection methods include penetrant inspection, magnetic particle inspection, and eddy current inspection. Because the workpiece to be detected needs to be cleaned before and after the penetration flaw detection, when the surface coating of the workpiece to be detected needs to be scraped, the detection cost is high, and the workpiece is not suitable for in-service detection; the magnetic powder detection is only suitable for ferromagnetic materials, and the ferromagnetic materials need to be demagnetized and cleaned after detection is finished, and the problems that the visual range is blocked and the like exist during service detection; the eddy current detection is widely applied to the detection of the complex curved surface workpiece due to the characteristics of rapidness, non-contact, high detection sensitivity, suitability for all conductive materials and the like. However, in the conventional single-probe eddy current inspection, in order to ensure the detection sensitivity, the coil size is usually small, and the efficiency of completing the scanning of a curved surface is very low. And because of the relative motion of the probe and the curved surface in the scanning process, the influence of lift-off effect inevitably exists; and a plurality of complex boundaries often exist in the workpiece, and due to the influence of the edge effect, a detection blind area exists near the boundary in single-probe eddy current detection, so that when the complex workpiece is detected by using an eddy current method, the effective detectable area is limited, and the application of the complex workpiece is limited.
The utility model discloses an array probe for curved surface work piece eddy current testing is exactly that the solution eddy current testing method of pertinence is used for the problem that complicated curved surface work piece detected and faces. The static profiling probe and the electronic scanning mode are adopted to replace a single probe for mechanical scanning, the lifting-off problem in mechanical scanning is solved, the problem of a detection blind area of the edge of a workpiece is solved by adopting a specially designed array coil arrangement mode and an electronic scanning sequence, and the effect of full-curved surface detection is achieved.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a time measuring is examined to the curved surface work piece to the technique of solving conventional eddy current testing, because carry away from the influence of effect and edge effect, the detection signal interference is big, the detection blind area is big, the problem that detection efficiency is low, provides an array probe for curved surface work piece eddy current testing, through the array coil of profile modeling design, the function of coil special arrangement mode and electronic scanning mode realization with static probe detection whole curved surface work piece surface.
The utility model discloses a realize like this:
an array probe for eddy current inspection of curved workpieces, comprising: the coil array is an integral structure formed by arranging a plurality of coils with the same size and parameters in an array mode surrounding a workpiece in a manner of embedding the coils into a profiling base which is adaptive to the three-dimensional shape of the workpiece to be detected.
Further, the above array probe for eddy current inspection of curved workpieces is characterized in that: the shape of the profiling base is the same as the structural shape of the curved surface workpiece, and the profiling base is made of an insulating material.
Further, the above array probe for eddy current inspection of curved workpieces is characterized in that: the coil is a flat coil, and the center of the coil is provided with a high-permeability iron-based amorphous alloy as a magnetic core, so that the coil has the property of magnetic field focusing.
Further, the above array probe for eddy current inspection of curved workpieces is characterized in that: the flexible material be flexible circuit board, two coil terminals of coil weld on flexible circuit board, make the coil possess the light, thin, the characteristics that can freely bend of quality, be convenient for laminate on the profile modeling base.
Further, the above array probe for eddy current inspection of curved workpieces is characterized in that: the flexible material and the profiling base are attached by using thixotropic insulating glue with good electrical insulating property, and the thixotropic insulating glue is immediately adhered to form a non-flowing uniform covering layer after contacting with the profiling base so as to achieve the effects of insulating and protecting the coil.
Further, the above array probe for eddy current inspection of curved workpieces is characterized in that: the coils are arranged in a mode that the coils are spirally arranged on the surface of the workpiece along an outer contour line to form an array; the distance between every two coils is the same and smaller than the outer diameter of the coil, so that the part between the coils can be detected to prevent missing detection.
Further, the above array probe for eddy current inspection of curved workpieces is characterized in that: the coil is a self-inductance coil which is an exciting coil and a detecting coil. When two coils which are adjacent at intervals in the array are used as excited coils, the coils are used as detection coils to acquire signals, and the defect information of the corresponding position of the surface of the detected workpiece below the coils is acquired.
The detection method of the array probe for the eddy current detection of the curved surface workpiece is characterized by comprising the following steps of: arranging a profiling base of an array probe for eddy current testing of a curved surface workpiece on the surface of the workpiece to be tested, wherein the distance between a probe edge coil and the edge of the workpiece is the same and is smaller than the outer diameter of the coil, and the axis of each coil is ensured to be vertical to the surface of the workpiece to be tested; the coils of the array probe for the eddy current detection of the curved surface workpiece are respectively connected with excitation signals under the control of a time-sharing multiplexer according to a set scanning mode and a certain spatial sequence and time sequence, two pairs of the excitation signals form a differential bridge, and output signals of the bridge are used as detection signals. If no defect exists, the influence of the state of the workpiece on the coil is the same, the output of the bridge is zero, when the defect exists, the impedance of the corresponding coil is influenced by the defect, the bridge is out of balance, and the output signal is in direct proportion to the variation of the impedance, so that the information of the defect is reflected.
Further, the detection method based on the array probe for the eddy current detection of the curved surface workpiece is characterized in that: each coil is respectively connected with 2 multi-way switches, the on-off of the switches is controlled by software, the 2 coils electrified at each moment can be combined at will, and the electrified coils are required to be in a completely symmetrical state, namely the positions of the two coils on a workpiece are completely consistent, so that the aim of eliminating the edge effect is fulfilled.
The detection principle is as follows: a plurality of coils with the same parameters are arranged to form an array, the array coils are tightly attached to the profiling base, the array coils are arranged from outside to inside along the outer contour line of the workpiece, the distance h between the outermost coil and the outer contour line of the workpiece is equal, the distance t between every two probes is the same, and t is less than the outer diameter d of the probes. Because the action range of the eddy current is 2 times of the outer diameter d of the coil, the design can ensure that the eddy current generated by the coil can completely cover the area between the two coils so as to avoid the condition of missing detection. An array probe measuring circuit is designed, each 2 coils and a resistor form a differential bridge circuit, and the output Uo of the bridge is obtained. Comprises the following steps:
z is the impedance of the coil at idle.
The output voltage is proportional to the amount of change in impedance.
When a sine wave signal with a certain frequency is applied to the bridge, the coil generates an alternating magnetic field around, the magnetic field generates eddy currents with the same frequency in a conductor (workpiece), the eddy currents also generate an alternating magnetic field, and the total magnetic field of the hinge in the coil is the superposition of the original magnetic field and the eddy current magnetic field, and the inductance of the coil changes from L = psi/I. Eddy currents also generate eddy current losses due to the presence of electrical resistance in the conductor, which energy losses are converted into the coil in the form of electrical resistance, so that the eddy currents cause a change in the coil impedance Z = R + jL. When a defect is present in the workpiece, the defect causes a change in the eddy current in that region and thus a change in the impedance of the coil.
When the surface of the workpiece is free of defects, eddy currents generated under the two coils are the same, the impedance changes of the coils are the same, and the output voltage of the bridge is 0. A defect is present in the workpiece, which defect causes a change in the impedance of the coil 1 if it lies within the range of action of the coil 1
At this time, the output voltage of the measuring circuit is measured
If a defect is located in the range of action of the coil 2, this defect causes a change in the impedance of the coil 2
Output voltage
Impedance changes due to the same defect, since the two coils are identical
. From the above analysis, it can be seen that when the defect is located in different coil action ranges, the phase difference of the output voltage is 180 degrees, thereby determining the position of the defect.
The oscillator outputs a sine wave signal with adjustable frequency, the sine wave signal is amplified by the power amplifying circuit to provide enough current for the probe, a probe detection signal is amplified by the amplifier and is sent to the phase sensitive detection circuit to detect the amplitude and the phase of the signal, and the size and the position of the defect are judged according to the amplitude and the phase. The detected signal is amplified and filtered by the conditioning circuit, is processed by the microprocessor after A/D conversion, is digitally filtered, stored, processed and imaged in the processor, and is displayed by the display. Through the arrangement of the scanning sequence in the human-computer interaction interface, the microprocessor controls the scanning sequence of the array probe through the multiplexing switch, and ensures that coils which are simultaneously accessed each time are always in completely symmetrical positions so as to avoid the influence of edge effect; and simultaneously, the scanning and traversing of all coils are ensured so as to avoid missing detection. And the scanning sequence is matched with an imaging software algorithm to output a visual detection result.
The utility model has the advantages that: the array coil with the profiling design, the special arrangement mode of the coil and the electronic scanning mode realize the function of detecting the surface of the whole curved surface workpiece by using the static probe, avoid the influence of the lift-off effect and the edge effect of single-probe eddy current detection in the prior art, solve the problems of large detection signal interference, large detection blind area and low detection efficiency, greatly improve the detection precision and the working efficiency and have great popularization and use values.
Drawings
Fig. 1 is a schematic diagram of the coil arrangement of the probe of the present invention.
Fig. 2 is a coil structure diagram of the probe of the present invention.
Fig. 3 is a schematic structural view of the profiling base of the probe of the present invention.
Fig. 4 shows a circuit diagram for measuring a coil according to the present invention.
Fig. 5 is a schematic diagram of the probe of the present invention.
Fig. 6 is a schematic block diagram of a detection system of the probe of the present invention.
In the figure, 1, a coil, 2, a flexible circuit board, 3, a profiling base, 4, a magnetic core, 5 and a coil terminal.
Detailed Description
Embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
As shown in fig. 1-6, a plurality of coils 1 with the same size and the same parameters are arranged to form an array in the manner shown in fig. 1, polyimide is used as a base material, the coils 1 are flat coils, and the coils are manufactured on a flexible circuit board 2 in a printed circuit manner, so that the printed circuit with high reliability and good flexibility is manufactured. In order to improve the detection sensitivity of the coil 1 and reduce the mutual influence between the coils 1, the magnetic core 4 is embedded in the center of the coil 1, the structure of the magnetic core is as shown in fig. 2, the magnetic core is made of iron-based amorphous alloy with high magnetic permeability, and two coil terminals 5 of the coil 1 are welded on the flexible circuit board 2, so that the coil 1 has the characteristics of light weight, thin thickness and free bending, and is convenient to be attached to the profiling base 3. The array coil shown in fig. 1 is tightly attached to the profiling base 3 shown in fig. 3, and the base material is made of flexible polyimide flexible material, so that the attaching surface can be ensured to be consistent with the surface of the workpiece. The profiling base 3 is made of a material which is an insulating material by taking the surface of a workpiece to be detected as a template.
The array coils shown in fig. 1 are arranged from outside to inside along the outer contour of the workpiece, and the arrangement direction is indicated by the dotted line in the figure. The distance h between the outermost circle coil and the outer contour line of the workpiece is equal, the distance t between every two probes is the same, and t is less than the outer diameter d of each probe. Because the action range of the eddy current is 2 times of the outer diameter d of the coil, the design can ensure that the eddy current generated by the coil can completely cover the area between the two coils so as to avoid the condition of missing detection.
The connection form of the array probe measuring circuit is shown in fig. 4, and each 2 coils and the resistor form a differential bridge circuit, and the output Uo of the bridge. Comprises the following steps:
z is the impedance of the coil at idle.
The output voltage is proportional to the amount of change in impedance.
When a sine wave signal with a certain frequency is applied to the bridge, the coil generates an alternating magnetic field around, the magnetic field generates eddy currents with the same frequency in a conductor (workpiece), the eddy currents also generate an alternating magnetic field, and the total magnetic field of the hinge in the coil is the superposition of the original magnetic field and the eddy current magnetic field, and the inductance of the coil changes from L = psi/I. Eddy currents also generate eddy current losses due to the presence of electrical resistance in the conductor, which energy losses are converted into the coil in the form of electrical resistance, so that the eddy currents cause a change in the coil impedance Z = R + jL. When a defect is present in the workpiece, the defect causes a change in the eddy current in that region and thus a change in the impedance of the coil.
As shown in fig. 5, when the surface of the workpiece is free of defects, the eddy currents generated under the two coils are the same, the impedance change of the coils is the same, and the bridge output voltage is 0. A defect is present in the workpiece, which defect causes a change in the impedance of the coil 1 if it lies within the range of action of the coil 1
At this time, the output voltage of the measuring circuit is measured
If a defect is located in the range of action of the coil 2, this defect causes a change in the impedance of the coil 2
Output voltage
Impedance changes due to the same defect, since the two coils are identical
. From the above analysis, it can be seen that when the defect is located in different coil action ranges, the phase difference of the output voltage is 180 degrees, thereby determining the position of the defect.
The scanning sequence of the coils is as follows: coil No. 2 and coil No. 4 are connected into the electric bridge, then coil No. 3 and coil No. 5 are connected, then coil No. 4 and coil No. 7 are connected, and the rest is repeated, and the scanning path is shown in figure 1. The coils connected at each time are two non-adjacent coils, so that a sufficient distance is ensured between the two electrified coils, and the condition that detection is missed due to the fact that impedance changes caused by the defects in the two coils are the same and the output of a detection signal is zero when the defects are just right positioned in the middle of the two adjacent coils is avoided. The distance between the two coils which are electrified every time and the edge is the same, so that the influence of the edge effect on the impedance of the coils is ensured to be the same, and the influence of the edge effect is eliminated.
Each coil is respectively connected with 2 multi-way switches, and the on-off of the switches is controlled through software. The 2 coils electrified at each moment can be randomly combined, so that the electrified coils are always in a completely symmetrical state (namely the positions of the two coils on the workpiece are completely consistent), and the aim of eliminating the edge effect is fulfilled.
The detection system is shown in a block diagram in fig. 6, an oscillator outputs a sine wave signal with adjustable frequency, the sine wave signal is amplified by a power amplification circuit to provide enough current for a probe, a probe detection signal is amplified by an amplifier, the amplitude and the phase of the signal are detected by a phase-sensitive detection circuit, and the size and the position of a defect are judged according to the amplitude and the phase. The detected signal is amplified and filtered by the conditioning circuit, is processed by the microprocessor after A/D conversion, is digitally filtered, stored, processed and imaged in the processor, and is displayed by the display. Through the arrangement of the scanning sequence in the human-computer interaction interface, the microprocessor controls the scanning sequence of the array probe through the multiplexing switch, and ensures that coils which are simultaneously accessed each time are always in completely symmetrical positions so as to avoid the influence of edge effect; and simultaneously, the scanning and traversing of all coils are ensured so as to avoid missing detection. And the scanning sequence is matched with an imaging software algorithm to output a visual detection result.
It should be noted that the above embodiments are only preferred embodiments of the present invention, and are only used for explaining the present invention, but not limiting the present invention, and those skilled in the art should be equivalent replacement modes without departing from the spirit and principle of the present invention.
Claims (7)
1. An array probe for eddy current inspection of curved workpieces, comprising: the coil array is an integral structure formed by arranging a plurality of coils with the same size and parameters in an array mode surrounding a workpiece in a manner of embedding the coils into a profiling base which is adaptive to the three-dimensional shape of the workpiece to be detected.
2. The array probe for eddy current inspection of curved workpieces of claim 1, wherein: the shape of the profiling base is the same as the structural shape of the curved surface workpiece, and the profiling base is made of an insulating material.
3. The array probe for eddy current inspection of curved workpieces of claim 1, wherein: the coil is a flat coil, and the center of the coil is provided with a high-permeability iron-based amorphous alloy as a magnetic core.
4. The array probe for eddy current inspection of curved workpieces of claim 1, wherein: the flexible material is a flexible circuit board, and two coil terminals of the coil are welded on the flexible circuit board.
5. The array probe for eddy current inspection of curved workpieces of claim 1, wherein: the flexible material and the profiling base are attached by thixotropic insulating glue with good electrical insulating property.
6. The array probe for eddy current inspection of curved workpieces of claim 1, wherein: the coils are arranged in a mode that the coils are spirally arranged on the surface of the workpiece along an outer contour line to form an array; the spacing between each coil is the same and less than the coil outer diameter.
7. The array probe for eddy current inspection of curved workpieces of claim 1, wherein: the coil is a self-inductance coil which is an exciting coil and a detecting coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020114618.1U CN211478151U (en) | 2020-01-19 | 2020-01-19 | Array probe for eddy current testing of curved surface workpiece |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020114618.1U CN211478151U (en) | 2020-01-19 | 2020-01-19 | Array probe for eddy current testing of curved surface workpiece |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211478151U true CN211478151U (en) | 2020-09-11 |
Family
ID=72362023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020114618.1U Expired - Fee Related CN211478151U (en) | 2020-01-19 | 2020-01-19 | Array probe for eddy current testing of curved surface workpiece |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211478151U (en) |
-
2020
- 2020-01-19 CN CN202020114618.1U patent/CN211478151U/en not_active Expired - Fee Related
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111189908A (en) | Profiling flexible array eddy current probe and detection method | |
| US5698977A (en) | Eddy current method for fatigue testing | |
| US6975108B2 (en) | Methods and devices for eddy current PCB inspection | |
| CN103499404B (en) | Ferromagnetic component alterante stress measurement mechanism and measuring method thereof | |
| US6040695A (en) | Method and apparatus for inspection of components | |
| CN111398413B (en) | Double-layer symmetrical differential plane eddy current detection sensor | |
| US20090167298A1 (en) | System and method for the nondestructive testing of elongate bodies and their weldbond joints | |
| CN109781838B (en) | Vortex-ultrasonic detection probe based on V-shaped coil excitation | |
| CN110702783A (en) | Array eddy current method for detecting thermal fatigue cracks of water-cooled wall tube | |
| CN112782274A (en) | Magnetic-gathering eddy current sensor | |
| US4881031A (en) | Eddy current method and apparatus for determining structural defects in a metal object without removing surface films or coatings | |
| Wincheski et al. | Self-nulling eddy current probe for surface and subsurface flaw detection | |
| CN107941904B (en) | Inspection probe and detection method in aerial metal path defective tube | |
| CN115406959A (en) | Eddy current detection circuit, method, system, storage medium and terminal | |
| Bernieri et al. | Characterization of an eddy-current-based system for nondestructive testing | |
| Malikov et al. | Subminiature eddy-current transducers for conductive materials research | |
| CN211478151U (en) | Array probe for eddy current testing of curved surface workpiece | |
| CN116519786A (en) | Electromagnetic identification method for surface defect morphology of metal with protective layer | |
| CN115078526A (en) | Method for detecting welding seam of pipeline or container by flexible array eddy current probe | |
| CN114002315A (en) | Multimode detection probe | |
| CN210269714U (en) | Non-contact flaw detection system based on rotating eddy current | |
| CN218412363U (en) | Eddy current detection probe and detection circuit based on combination of differential bridge and transformer conditioning circuit | |
| Qiu et al. | Normal magnetizing-based eddy current testing method for surface crack and internal delamination of steel plate | |
| JP2001108659A (en) | Eddy current prove for detecting metal surface flaw | |
| JPH0833374B2 (en) | Method and apparatus for detecting foreign layer in metal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200911 Termination date: 20220119 |